JP3784533B2 - Water-soluble film - Google Patents

Description

【００２９】
【発明の効果】
本発明の水溶性フィルムは、酸性物質、塩素系物質または農薬薬剤などをユニット包装した場合であっても、水溶性が経時的に低下しないという優れた作用効果を奏する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyvinyl alcohol (hereinafter abbreviated as PVA) film having excellent performance for packaging pharmaceuticals such as agricultural chemicals and fungicides.
[0002]
[Prior art]
In recent years, there has been a method (unit packaging) in which various chemicals such as agricultural chemicals are sealed and packaged in water-soluble films in unit quantities, put into water as they are in use, and the contents are dissolved or dispersed in water. Many have been used. The advantages of this unit packaging are that it can be used without direct contact with dangerous chemicals during use, that it does not require weighing during use because a certain amount is packaged, and the use of containers and bags used for packaging medicines The later processing is unnecessary or simple.
Conventionally, a partially saponified PVA-based film has been used as a water-soluble film for unit packaging. Conventional water-soluble films are excellent in cold water solubility and mechanical strength, but depending on the type of drug to be packaged, the water solubility of the film decreases over time during storage, making it insoluble or sparingly soluble in water. There was a problem.
[0003]
Examples of agents that make the partially saponified PVA film insoluble in water include alkaline substances, acidic substances, chlorine-containing substances, compounds having polyvalent metal salts such as copper and cobalt, polyvalent carboxylic acid-containing substances, and polyvalent amines. There are agrochemicals and fungicides such as contained substances, boric acid-containing substances, insecticides and herbicides.
As a film for packaging an alkaline substance, a PVA film modified with a carboxylate is known. Moreover, there is a report that a PVA film containing sorbitol has resistance to boric acid.
[0004]
Polyethylene oxide films and cellulose films are known as films for packaging acidic substances, chlorinated substances (such as bactericides), and agricultural chemicals, but their dissolution rate in water is very slow and mechanical properties are insufficient. However, since it is hard and brittle, the impact resistance at low temperatures is extremely small.
As a film for packaging agricultural chemicals, insecticides, etc., a water-soluble film is known in which an auxiliary agent such as polyethylene glycol and propyl gallate is blended with PVA and carboxylic acid ester-modified PVA (Japanese Patent Laid-Open No. 53-1993). No. 24351). Further, a water-soluble film for agricultural chemical packaging, which is obtained by blending a phenol derivative such as bisphenol A with 2-acrylamido-2-methylpropane sodium-modified PVA (Japanese Patent Laid-Open No. 7-118407) is known. However, conventional PVA-based films are water-soluble films that, when packaged with chemicals such as acidic substances, chlorine-containing substances, agricultural chemicals, and bactericides, will turn brown and become insoluble in cold or hot water. As a function was lost.
[0005]
[Problems to be solved by the invention]
The object of the present invention is excellent in mechanical strength, flexible and toughness, and retains initial water solubility even when a chemical such as an agricultural chemical or a bactericidal agent is packaged for a long period of time. It is to provide a water-soluble film.
A further object of the present invention is to provide a package formed by packaging an acidic substance, a chlorinated substance or an agrochemical.
A further object of the present invention is to provide a composition suitable for the raw material for producing the water-soluble film.
[0006]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventor has found that 100 parts by weight of a modified polyvinyl alcohol (A) having a sulfonic acid group and gallic acid or an alkyl ester (C) having 1 to 5 carbon atoms thereof (0.05) A water-soluble film comprising 20 parts by weight; a package formed by packaging an acidic substance, a chlorine-based substance or an agricultural chemical using the water-soluble film; 100 parts by weight of a modified polyvinyl alcohol (A) having a sulfonic acid group and gallic acid Or the composition which consists of 0.05-20 weight part of the C1-C5 alkylester (B) was discovered, and it came to complete this invention.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The modified PVA (A) having a sulfonic acid group used in the present invention has a sulfonic acid group added to a PVA which is a saponified product of a copolymer of a vinyl ester and a sulfonic acid group-containing monomer or a polyvinyl ester. It is a polymer obtained by reaction addition of a compound having the same.
[0008]
A saponified product of a copolymer of a vinyl ester and a sulfonic acid group-containing monomer is obtained by copolymerizing the vinyl ester and the sulfonic acid group-containing monomer in a bulk or alcohol solvent in the presence of a radical initiator. It can be obtained by partially or highly saponifying with an alkali or acid catalyst.
Here, examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl formate, vinyl versatate, vinyl pivalate and the like, but industrially produced and cost-effective vinyl acetate is usually used.
Any sulfonic acid group-containing monomer may be used as long as it contains a sulfonic acid group or a salt thereof in the molecule and can be copolymerized with a vinyl ester. Specific examples include 2-acrylamido-2-methylpropanesulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-methacrylamideamido-2-methylpropanesulfonic acid, and alkali metal salts thereof; ethylenesulfonic acid, Examples thereof include olefin sulfonic acids such as allyl sulfonic acid and methallyl sulfonic acid, and alkali metal salts thereof. Among these, 2-acrylamido-2-methylpropanesulfonic acid or an alkali metal salt thereof is most preferable from the viewpoint of copolymerization reactivity with a vinyl ester and stability during saponification. Here, Na, K, Li etc. are mentioned as an alkali metal. In addition, examples of the analog include salts such as ammonium and amine. In the case where the sulfonic acid group is in the acid form, it can be used in the present invention. However, in order to prevent hydrolysis of the vinyl ester during the copolymerization, the sulfonic acid group is partially or completely neutralized with an alkali metal. Is preferred.
Next, a modified PVA having a sulfonic acid group used in the present invention is obtained by saponifying a copolymer of a vinyl ester and a sulfonic acid group-containing monomer in an alcohol solution using an alkali or an acid catalyst. .
[0009]
A polymer obtained by reactive addition of a compound having a sulfonic acid group to PVA, which is a saponified polyvinyl ester, is a polymer in which a compound having a sulfonic acid group is introduced into PVA by an acetalization reaction or a Michael addition reaction.
The compound having a sulfonic acid group used in the acetalization reaction is an aldehyde compound having a sulfonic acid group such as butyraldehyde sulfonate and benzaldehyde sulfonate.
The compound having a sulfonic acid group used in the Michael addition reaction is an unsaturated compound having a sulfonic acid group such as 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, and alkali metal salts thereof.
In addition to these methods, a method in which an alcohol compound having a sulfonic acid group is added to PVA by an esterification reaction or a halogen compound having a sulfonic acid group is introduced into PVA by a condensation reaction is used.
[0010]
The content of the sulfonic acid group-containing unit in the modified PVA (A) is preferably 0.1 to 20 mol%, more preferably 0.5 to 10 mol%, and particularly preferably 1 to 5 mol%. In the case of a water-soluble film, the mechanical properties of the film are also important, and strength and flexibility are required even in the case of a thin thickness of 10 to 100 μm. Therefore, the viscosity of the modified PVA (A) The average degree of polymerization (hereinafter abbreviated as “degree of polymerization”) is preferably from 300 to 10,000, more preferably from 500 to 8,000. If the degree of polymerization is less than 300, the film strength tends to decrease. If the degree of polymerization is greater than 10,000, the viscosity of the solution when preparing the film increases and the workability decreases.
[0011]
The degree of saponification of the modified PVA (A) is required to show water solubility and chemical resistance when it is made into a film, and considering film strength, film waist, and bag-making property, 50 to 100 mol%, Preferably it is 80-100 mol%.
[0012]
The gallic acid or its C1-C5 alkyl ester (B) used for this invention is a compound which has the effect | action which prevents that a water-soluble film becomes insoluble in water. Specific examples include gallic acid and salts thereof, and esters of gallic acid such as methyl, ethyl, propyl, and isoamyl. Of these, gallic acid and propyl gallate are particularly preferred. The amount of component (B) is 0.05 to 20 parts by weight, preferably 0.2 to 10 parts by weight, more preferably 0.5 to 3 parts by weight, based on 100 parts by weight of component (A). is there. When the blending amount of component (B) is less than 0.05 parts by weight, the water solubility decreases during storage in a state where the drug is packaged and becomes water insoluble. On the other hand, when the amount of component (B) exceeds 20 parts by weight, the film strength is greatly reduced, or white powder is deposited on the film surface.
[0013]
In the water-soluble film of the present invention, in addition to the component (A) and the component (B), the hydroxycarboxylic acid (C) having reducibility is used in combination, so that the stability upon standing is drastically improved. Furthermore, coloring caused by polyvalent metal ions such as iron ions is also prevented.
Examples of the hydroxycarboxylic acid (C) having reducibility include citric acid, tartaric acid, L-ascorbic acid, malic acid, glucose and salts thereof. Among these, citric acid, tartaric acid, and L-ascorbic acid are preferable, and citric acid is particularly excellent. The compounding amount of component (C) is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, and particularly preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of PVA (A). .
[0014]
Since the water-soluble film of the present invention can be transported, stored and used even in hot and humid areas and cold regions, the strength and toughness of the film are required. Since particularly low temperature impact resistance is required, various plasticizers are used for the purpose of lowering the glass transition point of the film. Any plasticizer can be used as long as it is used as a plasticizer for PVA. Specific examples include polyhydric alcohols such as glycerin, diglycerin and diethylene glycol; polyethers such as polyethylene glycol and polypropylene glycol; phenol derivatives such as bisphenol A and bisphenol S; amide compounds such as N-methylpyrrolidone; Compounds obtained by adding ethylene oxide to polyhydric alcohols such as pentaerythritol and sorbitol; water and the like. These plasticizers may be used alone or in combination of two or more.
[0015]
As a film forming method, the component (B) and optionally the component (C) are added to an aqueous solution of the modified PVA (A), dissolved or dispersed, and then cast into a film, or an appropriate plasticizer or water. And melt extrusion film formation in the presence of At that time, if necessary, usual additives such as a colorant, a fragrance, an extender, an antifoaming agent, a release agent, an ultraviolet absorber, an inorganic powder, a surfactant, an antiseptic and an antifungal agent are appropriately blended. There is no problem. Moreover, you may add water-soluble polymers, such as PVA other than a component (A), starch, carboxymethylcellulose, methylcellulose, and hydroxymethylcellulose within the range which does not lose the characteristic of this invention as needed.
[0016]
As a drug packaged using the water-soluble film of the present invention, drugs such as acidic substances, chlorinated substances, agricultural chemicals and bactericides are preferable. In addition, drugs such as detergents, dyes and vegetation-related substances can be packaged.
The acidic substance is a substance that exhibits acidity when dissolved or dispersed in water, and examples thereof include agricultural chemicals, bactericides, and deodorants.
The chlorine-based substance is a substance containing chlorine in the molecule, and includes agrochemicals, bactericides, bleaches and the like. Specific examples include isocyanuric acid trichloride, isocyanuric acid dichloride, sodium salt of isocyanuric acid dichloride, N, N-dichlorohydantoin, N-chloro-N-bromo-5,5-dimethylhydantoin and the like.
Pesticides include chloropicrin, 1,3-dichloropropene, dichloroisopropyl ether and the like.
The shape of the drug may be granular, tablet, powder, or in some cases liquid. Further, it may contain a carrier such as talc, kaolin, bentonite, diatomaceous earth, a developing agent, a surfactant or a dispersant for improving the affinity for water or dispersing uniformly.
[0017]
According to the present invention, a composition comprising 100 parts by weight of component (A) and 0.05 to 20 parts by weight of component (B) is provided. Furthermore, according to this invention, the composition which consists of 100 weight part of component (A), 0.05-20 weight part of component (B), and 0.01-10 weight part of component (C) is provided. These compositions are also suitable for manufacturing raw materials such as fibers used for nonwoven fabrics, in addition to the manufacturing raw materials such as water-soluble films described above.
[0018]
【Example】
EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, “%” and “parts” are based on weight unless otherwise specified.
[0019]
Example 1
By adding a methanol solution of sodium hydroxide to a methanol solution of a copolymer obtained by copolymerizing vinyl acetate and sodium acrylamido-2-methylpropanesulfonate in a methanol solvent, and performing a saponification reaction, A modified PVA having a sulfonic acid group having a polymerization degree of 1700, a saponification degree of 88 mol%, and a sulfonic acid group-containing unit content of 2 mol% was obtained.
To 100 parts of this modified PVA, 1 part of propyl gallate, 0.2 part of citric acid, and 20 parts of glycerin as a plasticizer are added to create a uniform aqueous solution, which is cast onto a hot roll at 70 ° C. A modified PVA film having a thickness of 40 μm was obtained.
Bags (10 cm, 15 cm) were prepared using this modified PVA film. Into this bag, 35 g of a pool bactericide tablet containing trichloroisocyanuric acid as a main component was placed, and then heat sealed and sealed to obtain a package having a drug inside. Using a film in which polyethylene is laminated on the surface of aluminum (hereinafter abbreviated as “aluminum laminate film”), the outer side of the package obtained above is wrapped, and then heat sealed and sealed to form a double package. Created.
As an accelerated test of the long-term storage test, the double package packaged with the drug is left in a thermostat at 40 ° C. for 3 months, then the water solubility of the PVA film changes, the color of the PVA film and the double package package changes to aluminum. The odor with the laminate film removed was examined by the following method. The evaluation results are shown in Table 1.
[Method for measuring water solubility of PVA film]
The PVA film is cut into squares (40 mm, 40 mm), sandwiched between outer frames, immersed in stirring water (20 ° C., 10 ° C.), and the time (seconds) until the PVA film is completely dissolved Was measured. In addition, when it did not melt | dissolve in 30 minutes, it determined with water insoluble.
[Coloring of PVA film]
The evaluation results are indicated by the following symbols.
○: No coloration △: Slightly yellow color ×: Brown color [odor from the package]
The aluminum laminate film was removed from the double package, and an odor sensory test was performed in a state where the aluminum laminate film was packaged only with the PVA film. The evaluation results are indicated by the following symbols.
○: No odor △: Slight odor ×: Severe odor [0020]
Example 2
In the same manner as in Example 1, vinyl acetate and sodium acrylamido-2-methylpropanesulfonate are copolymerized and subjected to a saponification reaction, whereby the polymerization degree is 1250, the saponification degree is 97 mol%, and the content of the sulfonic acid group-containing unit. A modified PVA having 4 mol% sulfonic acid groups was obtained.
In the same manner as in Example 1, except that 1 part of propyl gallate, 0.5 part of citric acid, 10 parts of glycerin and 15 parts of diglycerin were added to 100 parts of this modified PVA. A modified PVA film was obtained.
Using this modified PVA film, a double package was prepared and evaluated in the same manner as in Example 1 except that a tablet of 30 g of toilet cleanser (sodium dichloroisocyanurate containing a surfactant) was packaged. did. The evaluation results are shown in Table 1.
[0021]
Example 3
In the same manner as in Example 1, vinyl acetate and sodium acrylamido-2-methylpropanesulfonate are copolymerized and subjected to a saponification reaction, whereby a polymerization degree of 1250, a saponification degree of 98 mol%, and a content of sulfonic acid group-containing units. A modified PVA having 4 mol% sulfonic acid groups was obtained.
The same as Example 1 except that 0.8 parts of ethyl gallate, 0.3 parts of L-ascorbic acid, 15 parts of glycerin and 10 parts of polyethylene glycol # 300 were added to 100 parts of this modified PVA. Thus, a modified PVA film having a thickness of 40 μm was obtained.
A double package was prepared and evaluated in the same manner as in Example 1 except that this modified PVA film was used to package a bactericide containing bromo, chloro-5,5-dimethylhydantoin. The evaluation results are shown in Table 1.
[0022]
Example 4
A modified PVA film having a thickness of 40 μm was prepared in the same manner as in Example 3 except that L-ascorbic acid was not blended.
Using this modified PVA film, a double-packed body in which a bactericide containing bromo, chloro-5,5-dimethylhydantoin was packaged was prepared and evaluated in the same manner as in Example 3. The evaluation results are shown in Table 1.
[0023]
Example 5
To a PVA aqueous solution having a polymerization degree of 1700 and a saponification degree of 99.6 mol% (adjusted to acidity with hydrochloric acid), 5 mol% of sulfonic acid benzaldehyde (amount based on vinyl alcohol units in PVA) is added, and sulfonic acid benzaldehyde is obtained by acetalization reaction. Was added to obtain a modified PVA having a sulfonic acid group.
Modified with a thickness of 40 μm in the same manner as in Example 1 except that 2.5 parts of gallic acid, 1 part of tartaric acid, 10 parts of glycerin as a plasticizer and 15 parts of diglycerin were added to 100 parts of this modified PVA. A PVA film was obtained.
Using this modified PVA film, a double package in which a pool bactericide was packaged was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0024]
Comparative Example 1
A modified PVA film having a thickness of 40 μm was prepared in the same manner as in Example 1 except that propyl gallate and citric acid were not added.
Using this modified PVA film, a double package in which a pool bactericide was packaged was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0025]
Comparative Example 2
A modified PVA film having a thickness of 40 μm was prepared in the same manner as in Example 2 except that propyl gallate was not added.
Using this modified PVA film, a double package in which toilet flushing disinfectant was packaged was prepared and evaluated in the same manner as in Example 2. The evaluation results are shown in Table 1.
[0026]
Comparative Example 3
An unmodified PVA film having a thickness of 40 μm was obtained in the same manner as in Example 1 except that unmodified having a polymerization degree of 1700 and a saponification degree of 88 mol% was used instead of the modified PVA having a sulfonic acid group.
Using this unmodified PVA film, a double package in which a pool bactericide was packaged was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0027]
Comparative Example 4
A modified PVA film having a thickness of 40 μm was obtained in the same manner as in Example 1 except that 7 parts of bisphenol A was added instead of propyl gallate.
Using this modified PVA film, a double package in which a pool bactericide was packaged was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0028]
[Table 1]

[0029]
【The invention's effect】
The water-soluble film of the present invention has an excellent effect that the water-solubility does not decrease with time even when an acidic substance, a chlorine-based substance, an agrochemical agent, or the like is packaged.

Claims (5)

A water-soluble film comprising 100 parts by weight of a modified polyvinyl alcohol (A) having a sulfonic acid group and 0.05 to 20 parts by weight of gallic acid or an alkyl ester (B) having 1 to 5 carbon atoms thereof. 100 parts by weight of a modified polyvinyl alcohol (A) having a sulfonic acid group, 0.05 to 20 parts by weight of gallic acid or an alkyl ester having 1 to 5 carbon atoms (B) and a reducing hydroxycarboxylic acid (C) 0. A water-soluble film comprising 01 to 10 parts by weight. A package formed by packaging an acidic substance, a chlorine-based substance, or an agricultural chemical using the water-soluble film according to claim 1. A composition comprising 100 parts by weight of a modified polyvinyl alcohol (A) having a sulfonic acid group and 0.05 to 20 parts by weight of gallic acid or an alkyl ester (B) having 1 to 5 carbon atoms thereof. 100 parts by weight of a modified polyvinyl alcohol (A) having a sulfonic acid group, 0.05 to 20 parts by weight of gallic acid or an alkyl ester having 1 to 5 carbon atoms (B) and a reducing hydroxycarboxylic acid (C) 0. A composition comprising 01 to 10 parts by weight.